Decreased labor tolerance often occurs in chronic pulmonary heart disease, which is a heart disease caused by chronic lesions of the lungs, thorax or pulmonary arteries that increase the resistance of the pulmonary circulation, resulting in pulmonary hypertension and right ventricular hypertrophy, and finally right heart failure, referred to as pulmonary heart disease. Its clinical features include cough, sputum, palpitation after activity, dyspnea, swelling of the lower limbs, emphysema and dilated pulmonary artery branches on X-ray, and enlarged right atrium or right ventricle on echocardiography. The course of the disease develops slowly. Firstly, patients mostly have a long history of chronic cough, cough or asthma, and gradually develop weakness and dyspnea, followed by gradual palpitations, increased shortness of breath and cyanosis, especially in the event of acute respiratory infections, ventilation disorders are further aggravated, thus causing hypoxia and carbon dioxide retention and leading to respiratory failure and heart failure. The following diseases may also be the cause of decreased work tolerance: 1. diastolic heart failure Diastolic heart failure (DHF) is a clinical syndrome of the pulmonary or physical circulation due to abnormal ventricular filling and elevated filling pressures in the presence of normal ventricular systolic function. 2, chickenbreast The sternum bulging forward is called chickenbreast (pectus carinatum, chickenbreast), chickenbreast is a common thoracic deformity, generally considered to be related to genetics, most people believe that the rib and rib cartilage overgrowth caused by the deformity of the sternum is secondary to the rib deformity. According to its different anatomical shape and surgical treatment, it is clinically classified into 3 types, namely keel chest, pouter pigeon breast and unilateral breast. Moderate and severe deformities will have adverse effects on the physiological and psychological development of the child and should be treated surgically. 3, aortic insufficency Aortic insufficency can be caused by lesions of the aortic valve and annulus, as well as the ascending aorta, and is more common in males, accounting for about 75% of patients; in females, it is accompanied by mitral valve lesions. In chronic cases, damage to the valve leaflets caused by rheumatic fever is the most common, accounting for two-thirds of all patients with aortic valve insufficiency. 4, coronary heart disease Coronary heart disease is short for coronary heart disease, also known as ischemic heart disease. It is a kind of heart disease caused by myocardial ischemia and hypoxia or myocardial necrosis due to organic narrowing or blockage of coronary arteries (i.e. atherosclerosis or power vasospasm). It mostly occurs after the age of 40 and is often seen in daily life. Clinical manifestations suddenly appear in the anterior chest area suffocating pain, shortness of breath, profuse sweating, pale face, the patient is forced to stop activities, the milder ones can relieve themselves within a few minutes and gradually return to normal after rest. 5. Pulmonary stenosis Pulmonary stenosis refers to the stenosis of the right ventricular funnel, the pulmonary valve or the common pulmonary artery trunk and its branches, etc. It can exist alone or as a component of other cardiac or organ malformations such as tetralogy of Fallot. Its incidence is about 10% of congenital heart disease. Pulmonary stenosis is most common in the pulmonary valve, accounting for about 90%, followed by stenosis of the funnel, while stenosis of the trunk of the pulsatile artery and its branches is rare.